1. Field of the Invention
The present invention relates to a method of injecting viscous fluid such as jam or cream into bread or confectionery, and particularly to a method of injecting viscous fluid into a product in a quantitatively and positionally regulated manner and on a continuous basis.
2. Description of Prior Art
Devices for charging, for example, cream into bread or confectionery, are known, and they include a switching valve, a piston and a nozzle. The nozzle is inserted into a product to inject and charge the cream in the product in that position. However, the charging devices have been designed to deal with products of a single shape or length, and have been unable to control the charging length of the filler. Further, in these devices, the nozzle is inserted into a product to charge the cream in the product, and the state of the filler in the product cannot be observed with the naked eye. Therefore, even if foreign matter is mixed into the filler material or the filler clogs in the nozzle or in a tube leading to the nozzle, thereby obstructing the delivery of the filler material to be charged in a product, such an error cannot be detected in the conventional devices.
Accordingly, products having the filler insufficiently charged cannot be distinguished from products having the filler charged properly, and, as a result, the filler is not always uniformly charged in the products, thus lowering the quality of the products.
Japanese Patent Publication No. 49464/85 teaches a device for charging a viscous filler such as chocolate cream into a split formed in the upper surface of bread. The device comprises a rotary valve, pump means for pushing the filler through the rotary valve into a cylinder, cylinder means for extruding the filler through the rotary valve to a discharge port for the filler, and shutter means for opening or closing the discharge port. Although this device can charge a controlled amount of the viscous filler into the split of bread, it has the pump means and shutter means in addition to the rotary valve and cylinder means, resulting in a complex mechanism which leads to high costs. Furthermore, this device has no nozzle through which a viscous filler is injected into bread.